With development of communications technologies, mobile terminals are increasingly widely used. In terms of a hardware structure, a mobile terminal is divided into two parts: an application processor and a modem.
When a mobile terminal receives a call setup instruction, a communication process between an AP and a modem is as follows:
Step a1. The AP sends a dial command to the modem when receiving the call setup instruction.
Step b1. The modem sends a request message to a network side according to the dial command.
Step c1. After receiving a response message that is fed back by the network side, the modem sets up a call and returns an acknowledgement message to the AP.
The acknowledgement message carries a call identity, and the call identity is used to identify this call.
Step d1. The AP changes an interface of the mobile terminal from a dial interface to a call interface according to the received acknowledgement message.
When a mobile terminal receives a hang-up instruction, a communication process between an AP and a modem is as follows:
Step a2. The AP sends a disconnect message to the modem when receiving the hang-up instruction, and the disconnect message includes a call identity of a to-be-terminated call.
Step b2. The modem sends a disconnect message to a network side.
Step c2. After receiving a response message that is fed back by the network side, the modem releases a resource of the call indicated by the call identity carried in the disconnect message, and feeds back a response message to the AP, to feed back a call termination success.
Step d2. According to the received response message, the AP exits from a call interface and returns to an initial interface.
In practical application, when entering a no-service area such as an elevator, the mobile terminal is disconnected from a network. In this case, when the mobile terminal receives a hang-up instruction, whether the mobile terminal is during a call or in a dial process, a relatively long time needs to be consumed to stop this call for the following reasons:
If a mobile terminal enters a no-service area during a call, when the mobile terminal receives a call termination instruction, the following process is performed:
Step a3. An AP sends a disconnect message to a modem, where the disconnect message includes a call identity of a to-be-terminated call.
Step b3. The modem sends a disconnect message to a network side according to the call identity, and starts a timer T305.
Step c3. After duration specified by the timer T305 expires, if the modem receives no response message that is fed back by the network side, the modem sends a disconnect message to the network side again and starts a timer T308.
Step d3. After duration specified by the timer T308 expires, if the modem still receives no response message that is fed back by the network side, the modem releases a resource of a call indicated by the call identity carried in the disconnect message, and feeds back a response message to the AP, to feed back a call termination success.
Step e3. According to the received response message, the AP exits from a call interface and returns to an initial interface.
In this scenario, when the mobile terminal receives a hang-up instruction, the mobile terminal does not terminate this call immediately, but terminates this call after a sum of duration specified by the T305 and duration specified by the T308 expires. Therefore, a disadvantage of a relatively long consumed time exists in a call termination process when the mobile terminal enters a no-service area.
If a mobile terminal enters a no-service area in a dial process, the mobile terminal checks a service status after receiving a dial instruction when the mobile terminal enters the no-service area. When checking that the service status at this time is an out-of-service state, the mobile terminal initiates a network searching operation and starts a redial mechanism at the same time (preset redial duration is 30 seconds). If a modem finds no network after the 30 seconds, the modem feeds back a response message to an AP and terminates this call. The AP cannot send a disconnect message to the modem if the mobile terminal receives a call termination instruction within the 30 seconds. In this scenario, a mobile terminal does not terminate a call immediately when the mobile terminal receives a call termination instruction, but terminates this call after preset redial duration expires. Therefore, a disadvantage of a relatively long consumed time exists in a call termination process of the mobile terminal.